The present invention relates to a plate width adjusting apparatus and a plate width adjusting method for a strip, which are used on a strip production line and the like.
A method using a trimmer has so far been known as a method for adjusting the plate width of a strip on a strip production line such as a pickling line and an annealing line. For example, as shown in FIG. 8, on a strip production line 50, there are provided trimmers 51, 51 at the right and left edge portions of a strip 53 transferred continuously in the lengthwise direction. The trimmer 51 has a pair of circular saws 52, 52, and is configured so that the circular saws 52 can be moved in the plate width direction (direction perpendicular to the transfer direction) of the strip 53. The trimmer 51 trims an edge portion exceeding a given specified width of the strip 53 passing between the circular saws 52, 52.
The above-described plate width adjusting method has a problem in that both edge portions of the strip 53 are disposed of as trim scrap, so that a loss in material is produced, leading to a decreased yield of product.
The present invention has been made to solve the above problem, and accordingly an object thereof is to provide a plate width adjusting apparatus and a plate width adjusting method that can increase the yield of product.
In accordance with the present invention, there is provided a plate width adjusting apparatus for adjusting a strip for a predetermined plate width, which is installed on a production line for the strip, comprising elongating means for elongating the strip being transferred on the production line in the transfer direction of the strip, characterized in that by the elongation of the strip in the transfer direction by using the elongating means, the strip is shrunken in the width direction, thereby adjusting the plate width.
In a preferred embodiment, the elongating means comprises tension generating means for giving tension in the transfer direction to the strip being transferred and bending means for giving bending force to the strip having been given the tension.
In a preferred embodiment, the apparatus further comprises detecting means for detecting the plate width of the strip, which is installed on the downstream side of the installation position of the elongating means in the transfer direction of the strip, and a detected value of the detecting means is compared with a preset specified value, by which the plate width is adjusted so that the plate width of the strip takes the specified value.
In a preferred embodiment, the apparatus further comprises cutting means for cutting edges of the strip, which is installed on the downstream side of the installation position of the detecting means in the transfer direction, and cutting control means for causing the cutting means to perform cutting operation on the basis of the detected value of the detecting means so that the strip has a predetermined specified width.
In a preferred embodiment, the apparatus further comprises correction means for correcting a warp in the strip by giving a vertical pressure to the strip.
In another aspect of the present invention, there is provided a plate width adjusting method for adjusting a strip for a predetermined plate width on a production line for the strip, comprising the steps of elongating the strip being transferred on the production line in the transfer direction of the strip; and shrinking the strip in the width direction by means of the elongation of the strip, thereby adjusting the plate width.
In a preferred embodiment, the strip is elongated by giving tension in the transfer direction to the strip being transferred and by giving bending force to the strip having been given the tension.
In a preferred embodiment, a warp in the strip is corrected by giving a vertical pressure to the strip having been elongated.
According to the present invention, the strip is elongated in the transfer direction and is shrunken in the width direction thereof, by which the plate width of the strip can be adjusted. Therefore, narrow trim scrap is not produced by the cutting of both edge portions of the strip at the time of plate width adjustment for the strip, so that a loss in strip material can be eliminated, whereby the yield of product can be increased.
Also, tension in the transfer direction is given to the strip and bending force is given to the strip to elongate the strip, by which the strip can be elongated easily and sufficiently. Therefore, desired plate width adjustment can be made securely.